Present day engines control oil leakage past a piston in the cylinder through the use of oil control rings in a groove of the piston. However, the oil rings have gapped ends which permit oil leakage, thus, increasing the oil consumption rate. Furthermore, oil leakage may also occur as the oil flows into the groove and out of the groove over the upper ring surface. The oil leakage, while increasing the oil consumption rate, further adversely affects the emissions of the engine whether the leaked oil is burned or remains unburned prior to entering the exhaust stream.
An oil control ring design is disclosed in U.S. Pat. No. 5,251,915 issued to Paul R. Meernik on Oct. 12, 1993 wherein the oil control ring is used for a piston and has a single low tension rail and a contiguous blocker ring, under light tension, to prevent oil flow through the rail end gap. A separator ring behind the blocker ring allows oil flow to a drainage vent to help keep the region behind the blocker ring dry. A dike behind the blocker ring in the form of a closed ring or a recess formed in the piston groove collects oil thrown upwardly on the upper half of the piston cycle to prevent oil leakage through the upper axial clearance or blocker ring end gap. This design incorporates the use of four to six separate members in order to accomplish side sealing. The four separate members are complicated to manufacture and to assemble into the piston groove, increasing the costs associated with the design. Additionally, this design does not have the means to gap seal the oil control ring completely. A potentially significant oil escape path bounded by the cylinder wall, the bottom outer surface of the blocker ring, and the top outer chamfer of the rail exists allowing oil to flow from the end gap of the rail along the top outer chamfer and through the end gap of the blocker ring.
The present invention is directed at overcoming the problems as set forth above.